problem 2 - STM & WMM Flashcards
what is a chunk
a memory unit that consists of several components that are strongly associated with one another
millers magic number 7
7 +/- 2
STM has limited capacity of between 5-9 items
what is the Brown,Peterson & Peterson technique
used to assess how much info STM could hold
involves presenting p’s w some items that they are instructed to remember → P’s then perform a distracting task → after distracting task, p’s are asked to recall the original items
what is the serial position effect?
the U shaped relationship between a words position in a list & its probability of recall
curve shows strong recency & primacy effects
recency vs primacy effect
recency effect = better recall of words at the end of the list - occurs bcuz the final words were still in the STM at the time of recall
primacy effect = enhanced recall for items at the beginning of the list
- presumably remembered for 2 reasons: (1) they don’t need to compete w any earlier items & (2) we rehearse early items more frequently
proactive vs retroactive interference
proactive interference = people have trouble learning new material bcuz previously learned material keeps interfering w their new learning
- primacy effect
retroactive interference = new memories disrupt the retrieval & maintenance of old memories
- recency effect
Wickens et al research (release from proactive interference)
demonstrated that release from PI could also happen when the semantic category of the items was shifted
- employed 5 semantic categories & initially gave p’s 3 trials on the BPP test
- on each trial they saw 3 related words (e.g. given jobs for trials 1,2&3, but then given fruits on trial 4)
- remembered fruits really well & didn’t suffer from PI
- BUT those whose category changed from vegetables to fruits still suffered from PI due to semantic similarity
conclusion: the number of items stored in STM depends on both chunking strategies & word meaning
what is the central executive?
- PL & VSS are slave systems used by the CE for specific purposes = is heavily involved in almost all complex cog activities but does not store info
- prefrontal cortex
- associated w several executive processes
Baddeley’s 4 executive processes
- Focusing attention or concentration
- Dividing attention between 2 stimulus streams
- Switching attention between tasks
- Interfacing w LTM
Miyake et al’s executive functions
identified 3 related (but separable exec functions):
- Inhibition function = used to deliberately override dominant responses & to resist distraction
- Shifting function = used to switch flexibly between tasks or mental sets
- Updating function = used to monitor & engage in rapid addition or deletion of WM contents
Miyake & Friedman (2012) unity/diversity framework
Each exec function consists of what is common to all 3 functions + what is unique to that function
- Common to all: ability to actively maintain task goals & goal-related info + use this info to effectively bias lower-level processing
what is dysexecutive syndrome?
a condition in which damage to the frontal lobes causes impairments to the CE
have problems with:
- Task setting = the ability to set a stimulus response relationship (planning)
- Monitoring = checking the adequacy of one’s task performance
- Energisation = sustained attention or concentration
- Metacognition = recognizing differences between what you know & what you believe
what is the phonological loop?
processes & stores info briefly in a phonological (speech based) form
- Preserves the order in which words are presented
Consists of 2 components:
- A passive phonological store directly concerned w speech perception
- An articulatory process linked w speech production giving access to the phonological store
what is the phonological similarity effect?
the finding that immediate serial recall of verbal material is reduced when the items sounds similar
- doesn’t only involve the PL: semantic processes also play a part
- depends more on acoustic than articulatory similarity
what is the word length effect?
the finding that verbal memory span decreases when longer words are presented
- when p’s engaged in articulatory suppression to prevent rehearsal: eliminated the WLE w visually presented words = the effect depends on rehearsal
what is orthographic neighborhood?
consists of words of the same length differing in only 1 letter
- Short words have more ‘neighbors’ than long words - when short & long words were equated for neighborhood size, the WLE disappeared = WLE may be due more to neighborhood size
what is the visuo-spatial sketchpad?
- Stores & manipulates spatial & visual info
- Visual processing involves remembering what, spatial processing involves remembering where
Consists of 2 components:
1. Visual cache = stores info about visual form & color
2. Inner scribe = processes spatial & movement info
- is involved in the rehearsal of info in the visual cache & transfer info from the visual cache to the CE
evidence for notion of separate visual & spatial systems
Smith & Jonides (1997)
- 2 visual stimuli presented together followed by a probe stimulus
- P’s decided whether the probe was in the same location as one of the initial stimuli or had the same form
- more activity in the right h during spatial task & more activity in the left h during the visual task
Zimmer (2008)
- Areas in the occipital & temporal lobes were activated during visual processing
- Areas in the parietal cortex were activated during spatial processing
Klauer & Zhao (2004)
- spatial interference task disrupted performance more on spatial main task
- visual interference task disrupted performance more on visual main task
what is the episodic buffer?
- Provides temporary storage for integrated info coming from the VSS & PL
- Holds integrated info about episodes or events in a multi-dimensional code combining visual, auditory & other sources of info
- Acts as a buffer between the other components of WM + links WM to perception & LTM
what are the 2 key assumptions concerning the CE, PL & VSS?
all have limited capacity & can function fairly independently of the others.
2 key assumptions:
1. If 2 tasks use the same component, they cannot be performed successfully together
2. If 2 tasks use diff components, it should be possible to perform them as well together as separately
what is articulatory suppression?
rapid repetition of a simple sound which uses the articulatory control process of the PL
- prevent rehearsal
Evaluation of the WM model
+ More active than the Atkins model, not just storage but active processing too
+ Accounts for spatial deficits in brain damaged people’s STM → only selective deficits not overall
+ Less emphasis on verbal rehearsal in the phonological loop than previously
- Oversimplified: smell & taste are not included, spatial is not specific
- Too little research on the interactions among the components
the maxispan procedure
Only rehearsing the first items over & over → articulatory suppression prevents further storage in the phonological loop
- the rest will automatically go into the executive loop
- Prevents transfer between the 2 systems for maximum efficiency
Barouillet et al (maxispan) - method
aim: testing hypothesis that maxispan procedure elicits higher letter spans than the simple span procedure
2 conditions: maxispan & simple span (given no instructions on rehearsing or refreshing techniques & usually overload the phonological loop)
Method:
- Lists of consonants, all letters presented visually but different colors
- Lists were presented in increasing length
- BLUE letters were rehearsed in the PHONOLOGICAL loop
- BLACK letters were only refreshed in the EXECUTIVE loop / episodic buffer
Barouillet et al (maxispan) - results
Proportion of black letters correctly recalled decreased when the no. of blue letters to rehearse increased
- Strong primacy effect on both conditions but only a small recency effect
Maxispan condition: black letters better recalled
- Serial position only affected the black letters - no serial position effect for the blue letters (rehearsed letters) if there were up to 4 blue letters
- Stronger primacy effect
Simple span condition: the rate of recall decreased as serial position increased
Barouillet et al (maxispan) - conclusion
Maxispan procedure effectively uses both systems
When capacity of the PL (blue letters) is not fully used (i.e with 3 or less units), there is no difference between the 2 groups.
- A difference only arises when the full capacity of the PL is used = then the maxispan procedure works better
On the other hand, when the capacity of PL is exceeded, fewer black letters are remembered - bcuz part of the central attentional system is occupied by overloading the PL
Rehearsing vs refreshing strategies
Rehearsing strategy uses the phonological loop and takes more time
Refreshing strategy can be very fast mechanism and is used by attentional system
